diff --git a/src/httprpc.cpp b/src/httprpc.cpp
index daac7a0f1a..8ac6925acd 100644
--- a/src/httprpc.cpp
+++ b/src/httprpc.cpp
@@ -112,7 +112,7 @@ static bool multiUserAuthorized(std::string strUserPass)
             std::string strSalt = vFields[1];
             std::string strHash = vFields[2];
 
-            unsigned int KEY_SIZE = 32;
+            static const unsigned int KEY_SIZE = 32;
             unsigned char out[KEY_SIZE];
 
             CHMAC_SHA256(reinterpret_cast<const unsigned char*>(strSalt.c_str()), strSalt.size()).Write(reinterpret_cast<const unsigned char*>(strPass.c_str()), strPass.size()).Finalize(out);